Suspension of vehicles



g- 1 1941- P. H. MISTRAL 2,253,190 v SUSPENSION OF VEHICLES I Filed Jan.14. 1959 5 Sheets-Sheet 2 INVENTOR; PAUL H ENRI M ISTRAL AT'fowgvq Aug.19, 1941. P. H. MISTRAL SUSPENSION 0F VEHICLES Filed Jan. 14, 1959Sheets-Sheet 5 C v INVENTOR= PAUL HENRI MLSTRAL ATTORN 5Y6 Aug. 19,1941. P, M|$TRAL 2,253,190

SUSPENSION OF Y'VEHICLES Filed Jan. 14, 19:59 7 5,5heets-Sheet 4 ENTORQv INV .7 PAUL HENRI MISTRAL,

Aug. 19., 1941. P. H. MISTRAL 2,253,190

SUSPENSION OF VEHICLES Filed Jan. 14, 1939 5 Sheets-Sheet 5 PAUL H EN RIM |5TRAL -Bymw f AT TOR N 5V5 Patented UNITED? STATES I PATENT OFFICE2,253,190 SUSPENSION OFWEHICLES I P aul llenri Mistral,-.l!aris, FranceApplication January 14,1939, Serial No. 250,882

\ 'lnFrance January 19, 1938 6 Claims; (01.280- -124) The.inventionrelates tothe suspension of vehicles, in 1 particularautomobile. vehicles, of the. double track type that isto-say which reston the ground by means-oi wheels arranged in pairs,: the wheelsuof one*pair. havinga transversely di-' rected. axis of rotation;

Such :vehiclesgwhile traveling, are frequently subjected" cto .:efforts1which: are unsymmetrical with respect :to the longitudinal axis, viz;ef-' forts arising due to unevennessof the rolling surface, efiorts dueto the action of centrifugal force when negotiating curves. .effectroftransverse de- 7 clivitieainnthe roadwsurtacer. Such: efforts tend tocause uuntimelylinclinations .of the vehicle. which are detrimentaltothe safety and to the comfort of theoccupants.

The inventionwhas for .itscobject to eliminate. these drawbacks in asimple and eflicient man+ her by providinganarrangement wherein thesuspended partof the vehicle restsgon the min-'- Under these conditionswhen thevsuspended 30 part corresponding to oneside of the. vehicle,becomes deformed, the part of the suspension corresponding to the otherside will be automatically. deformed ordevelopa tendency of becomingdeformed: in; the xsamermanner. The substantial result of this is that,for example, a plane'which is rigidly connected. to the suspended partof. the vehicle and under normal conditions is parallel to the rollingsurface, will remainsparallel to saidsurface during. the time ofoperation of the vehicle. 5

member of each of the hydraulic devices on both sides of the vehicleareinterconnected by means of a first hydraulicconnection. between spaceslocated in one of the devices on a certain side with respect to themovable member in the other device onthe other side of the movablemember respectively a second hydraulic connection being establishedbetween the two remaining spaces located difierently with respect totheir respec- 1n tive movable member from the first named spaces.

The invention also covers a hydraulic arrangement comprising meansprovided on each of the' hydraulic connections, forcausing the liquid tocirculate more readily in one direction than in the other and, moreprecisely for causing the liquid to circulate more readily in thedirection corresponding. to the depression of the suspension proper thanin that which corresponds to its re- 20 laxation. Thus, in a very simplemanner, an

arrangement is obtained which acts both as a shock-absorber andstabilizer.

The inventionthus provides a hydraulic connection between theshock-absorbing devices be- 25 longing to each of the sides of thevehicle, said hydraulic connection being such that the movements of themovable members of the shock-absorbers shall be alike and take place inthe same direction.

Several embodiments of a shock-absorbingstabilizing arrangementaccording to the invention will be described hereafter with reference tothe-accompanying drawings in which:

Fig. 1 is a diagrammatical View, in vertical sec-' .35 tion, of ashock-absorbing-stabilizing arrangement according to the invention;

Fig. 2 is a section along the line 2--2 of Fig. 1; Fig. 3 is asectionalong the line 33 of Fig. 1;

Fig. 4 is a very simplified perspective view, showing the relativearrangements of the shockabsorbers and of the valve boxes;

the actionof centrifugaLfor-ce; the correspond- In particular, when;while 'egotiating a curve, 5 is a diagra a front View. P the part oithesuspension hich corresponds to tial section, of another embodiment ofthe shockone of-thesidesof the .vehicleis depressedunderabsorbing-stabilizing, arrangement according to E5 the invention;ingpart. of the suspension on'theother' sideiis depressed the sameamount, so: that thegntire fl rangement; suspended part of thevehiclewill be lowered.v Fig. 7 shows a vertical section of another em-Whennear the edge-of a high crowned road bodiment of a shock-absorbingdevice; bed, the depression of-zthe suspension obta ningi Figciiis a dierammatical general view of a on the lowermost side .of the'vehicle is c7 per 1 Y shock-absorbing/gevice shown in Fig. 7. sated by acorresponding depression of the su s--v reference w l first be had toFigs. 1 to 4 which pension belonging totheother side. i. owdiagrammatically a sh ck-absorber-stabiliz'er deviceaccording to thenvention, adapted for use on either the front orthe rear wheel In' thearrangementkaccording to the invention/i spaces located on' either sideof the movable Fig. 6 shows a section of a detail of said artrain of anautomobile vehicle. Such device comprises a first hydraulic mechanism A,by

means of which one side of the suspended part of the vehicle issupported by the unsuspended part, a second similar mechanism A beingprovided for supporting the other side; these hydraulic mechanisms areconnected to each other by means of a double hydraulic connection B onwhich are interposed valve boxes C and C The hydraulic device A, forexample, is pro vided with a cover I comprising a cylindrical body 2 onwhich is fitted a cap 3 formed with an upwardly extending lug 4 havingan eye5 for the pivotal connection to the chassis of the vehicle.

Fitted into the inner face of cap 3 is a piston rod 6 extending througha central opening 1,

of a wall 8 forming the upper end of an outer cylinder 9, as well asthat of a coaxial inner cylinder I0. An annular open space II is formedbetween the outer surface of cylinder I and the inner surface ofcylinder 9 respectively; .on the piston rod 6 is fixed a piston I2delineating an upper chamber I3 and a lower chamber I4, and is adaptedfor sliding movement in the inner cylinder III. The upper chamber I3communicates with the annular space II through an orifice I provided atthe upper part of the cylinder I0. The diameter of the body 2 of thecover I and that of the outer cylinder 9 are such that the cover I andsaid cylinder can move in sliding engagement to each other. The lowerportions of cylinders 9 and III respectively are closed by a commonbottom part I6. The part I6 is provided with an axial bore I1, formingpassage for the piston rod 6. It is furthermore provided with a radialchannel I8 communicating with the annular space II and which is extendedby a vertical passage I9 opening into an orifice 28. The part I6 isprovided with a second vertical passage 2| which opens, at its upperpart, into the chamber I4 and, at its lower part, into an orifice 22diametrically opposite the orifice 20. The bottom part I6 is surroundedby the plates 23 and 24 which form a part 25 for connecting to theunsuspended part of the vehicle, for example. The plates 23 and 24 areprovided with openings 26 and 21 which respectively extend the openings20 and 22.

, The construction of the device A is similar to that of device A. Inthe drawings, like parts of the two devices have been marked with likereference numerals, the parts relating to the device A bearing the index1.

From the opening 21 (device A) extends a tube 28 which opens through anorifice 39 into the lower chamber 29 of a. valve box C. The chamber 29is'closed, downwardly by a bottom part 3I, laterally by a cylindricalbody 32 and upwardly by a partition 33 provided with wide peripheralperforations 34 and with a central orifice 35. On the partition 33 restsa washer 36 provided with a central orifice 31. An upper orifice 38, onthe body 32 is arranged in such manner as to open into the lower chamber29 as soon as the washer 36 is lifted from the partition 33. Undernormal conditions, the washer 36 remains resting on the partition 33under the action ofa light spring 39. With the orifice 31 co-operates aneedle valve 40 on the collar 4I on which'bears the spring 39. The upperface 42 of said collar forms a helical slope which co-operates with aconjugated helical slope formed at the base of a small block 43 whichfurthermore acts as a housing for the tail 44 of the needle valve whichis held against rotation by 75 a rib 45. Said small block 43 isrotatably mounted in an intermediate part 46 secured to the body 32; itsupper end receives, by keying, the head 41 of a lever 48, the other endof which is connected, by means of a stud 49, to a connecting rod 50,with a maintaining washer 5|. A stuffing-box 52 makes the valve boxfluid-tight. From the upper orifice 38 extends a tube 53 which opensinto-the orifice 26 The construction of the valve box C is similar tothat of the valve box 0. Its lever 48 is likewise mounted, by means of astud 49 on the connecting rod 50. The lower orifice of the valve box 0communicates, through a tube 54, with the orifice 21 the upper orifice38 communicates, through a tube 55, with the orifice 26 (Fig. 3). Thewhole system is filled with a liquid, for example oil,

The operation of said system is as follows: Under normal conditions,that is to say when inoperative, and the vehicle being loaded as pro- 1vided for, the various members are in the position shown in Fig. 1. I

If, for any reason, the suspended part of the vehicle m'oves downwardson one side, for example if the piston I2 slides downwards in thecylinder II) in the direction of the arrow 1, a part of theliquidcontained in the chamber I4 is forced through the passage 2I, theorifices 22 and 21, the tube 28, into the lower chamber 29;

the infiux of liquid lifts the washer 38 against the action of the lightspring 39 and the liquid flows without appreciable resistance throughthe perforations 34 directly into the tube 53. It fiows through theorifices 26 and 20 through the passage I9 the radial channel I8 theannular space H, penetrates into the cylinder I0 and pushes the pistonI2 downwards, in the direction of the arrow j, the same distance as thepiston I2 has moved downwards. The liquid contained in the chamber I4 isdriven through the. passage 2I the orifices 22 and 21 and the pipe 54 upto the lower chamber 29 of the valve C it pushes back the washer 36 andflows, without considerable resistance, into the tube 55 which conveysit, through the orifices 26 and 29, the passage I9, the radial channelI8, the annular space II, the orifice l5, into the upper chamber l3where it instantly fills the space left free by the depression of thepiston I2.

It will therefore be seen that, by means of the system according to theinvention, the deformation of the part of the suspension'correspondingto one side of the vehicle is accurately reproduced by the part of thesuspension belonging to the other side.

During the relaxation of the suspension that follows the depressionphase which has just been described, the pistons I2 and I2 move againupwards. The piston I2 pushes the liquid contained in the chamber I3; infront of it which will then circulate in the annular space II, theradial channel I8, the passage I9, the orifices 20 and 26 and the tube55. When arriving'from the valve box C the liquid in order to reach thelower chamber 29 passes through the space left vacant between the needlevalve and the .central orifice 31 Said space is so dimensioned that theliquid will be subjected to an effective braking action as it passes. Itmust -Iect,"as described above.

. pension has been relaxed said liquid fills the space vacatedby theforward movement of the piston I2 The forward movement of said pistonhas, in the same manner, driven liquid into the chamber I4, through theannular space Il the orifices 2II and 25 the tube 53; the valve box C,the orifices 21 and 22,-and thepassage 2I. by the upward movement of thepiston I2. When the liquid from the valvebox C circulates in thisdirection, it undergoes an effective braking ef- It will therefore beseen that the rebound" effect, which wculd'be caused by the too suddenexpansion of the resilient suspension of "the vehicle, is preventedbythe braking that the liquid undergoes both in the valve box C and in thevalve box C The control of the shock-absorbing effect is carried outinthe simplest manner. By push-- ing in the needle valve 49, the freecross-section for the passageof the liquid is narrowed between saidneedle valve and the walls of the orifice 31 provided in the washer 35.The push ing in of the needle is efiected, for example for the valve boxC,by rotating the lever48. This rotation involves that of the block 43,andthe conjugated helical slopes both of said block and of the collarcause the needle 40 to mov downwards or upwards according to the direc-'tion of rotation of the lever 48. The coupling of the levers 48 and 48enables, by the sole opera tion of the connecting rod 50, for'examplefrom the instrument'panel, by means of a fiexible transmission, thebraking efiect caused'by each 1 of the valve boxes C and C to besimultaneous};

adjusted to the same value. It is therefore thus possible to modifyinstantly the flexibility cf the suspension as a whole while the vehicleis running. This adjustment is effected withoutmodifying the hydraulicdevices A and A which,

. another gas may be introduced Into the cover ,I

and I for example by means of vaves provided on the ends 3 and 3 of saidcovers. In this case, of course, a perfect fluid-tightness is obtainedbetween the cylindrical bcdy 2 of the cover I and the outer cylinder 9and also between the body 2 and the cylinder 9 so that a perfectsuspension is thus obtained.

Fig. 5 shows diagrammatically a general view of a somewhat modifiedembodiment, in which each side is provided with a hydraulic device D andD respectively each cooperating with a compensating box, E and Erespectively. Inthe transmissions interconnecting the devices D and Dare provided valve boxes C andf. of similar construction as thosedescribed above.

The device D comprises a cylinder body 51 having an upper end '58 and alowerend 59; an

eye TII provided in the lower end by means whereof, for fixing the axleII of t e vehicle, or. any suitable part attached thereto may be fixed.

Said liquid fills the space left empty nected to the vehicle body bymeans of an eye the lower end 69. The piston I2 thus delimits anupperchamber and a lower chamber I6 respectively. .An orifice" at thebase of the cylinder 61 opens into a tube I8 leading to the orifice30 ofthe valve box C. At the upper part of the cylinder 61 is provided anorifice I3 into which opens, a tube 80 leading to the orifice 33 of thevalve box C The device D which is of the same construction as the deviceD, is connected through the upper orifice I9 by means of a tube 8|, tothe orifice 33 of the valve C; the lower orificell is connected throughthe 82 to the orifice 30 of the valve C The compensating valve Ecomprises a body 83 which is secured to the piston rod 13 and con- 84.In the body 83 is provided a housing 88 (see Fig. 6) for a needle valveblock 81 which rests, by its proper weight, on the wall 88 of saidhousing, and the. point 89 of which is opposite a corresponding conicalseat 90 having a central orifice 9| opening into a reservoir 92. orifice93 establishes communication of the housing 86 with a channel whichextends all along the piston rod 13 andopens, through an orifice '95,into the chamber I6.

A plug 96 is fitted on top of the reservoir-92. The construction of thecompensating valve E is similar to that of the valve 'E. V x l Theoperation of this hydraulic system is the same as that whichhas beendescribed above; During the operative periods, the over-pressureprevailing in the hydraulic circuit bears the needle valves 81 and 81against their seat 30-90 thereby isolating the circuit from the outside.When inoperative, the expansions or contractions of the liquid in saidcircuit are I compensated for by the transferoi liquid into or from thereservoirs 92-32 by passing between the needle-valves and their seat.

In Fig. '7 an embodiment has been shown of a hydraulic device whichbelongs to one of the sides of the vehicle and in which the pistons movehorizontally. In this embodiment, the body I of the device limits thereservoir I21 for the liquid. It is capped by a cover I28. It isprovided with cylindrical" bearing surfaces I29 and I30 in which slidethe plunger pistons HI and I32 respectively which are secured to eachother by a collar I33. Leather packings I34 and I35 ensurefluid-tightness of the sliding. The piston I3I moves inside a chamber I36 whereby the actual volume of the chamber may be varied. The pistonI32 moves inside a similar chamber I31. The chambers I36 and I3! arerespectively formed in ends I38 and I39 which are fitted on the bodyI26. The latter is fixed, by any suitable meanasuch as bosses I20 andI2I to the chassis of the vehicle. The collar I33 is provided with aplane groove acting as a housing for a square I40 having a centralopening I4I whichreceives a finger I42 that'forms the end of a crank pinI43 fixed on a shaft I44 by means of a clamping of a collar I 45.Connected by means of grooves I45 to the shaft I44 is an arm I4'I, theend I48 of g which is connected to a member secured to the wheel. Thechamber I36 is connected,

, through a channel I49, to a housing I50 in which is lodged a needle,valve I5I which is locked against rotation and co-operates .with anopening I52 provided in a ring I53 which is urged against its seat I54by a light spring I55. Said spring bears on a circular projection I56provided on the needle valve I5I. The tail I5I of the latter is lodgedin a hole I53 provided in a tube small. block I59 which is provided witha helical slope I60 co-operating with a conjugatedhelical slope I6I of awasher I62 which is interposed between the block I59 and the circularprojection I56. The small block I59 is rotatably mounted in the body I63and its end is connected, by means of a key I64, to an adjusting leverI65. Bolts I66 connect the body I63 to the end I38. The housing I50communicates, through an orifice I61, with a tube I68. The chamber I31,in turn, is in communication with a tube I10 through an orifice I68.

The device for compensating, filling and exhausting the air, for each ofthe chambers I36 and I31, comprises a valve "I which, under normalconditions, rests by its proper weight on a wall I12 whereby an orificeI13 in this wall serves to establish communication between the valvehousing I14 and the chamber I36. The tail I15 of the valve I1I is guidedin a guide member I16 which is screwed into a boss I11 of the wall I26of the reservoir. The seat I18 for the valve forms the orifice of aconduit I19 which opens into said reservoir. The guide member I16 has abore I16 for the exhaust of the air as may be contained in the circuit.

A general view of a wheel train of an automobile vehicle equipped withthe devices which have just been described is shown in Fig. 8. On theaxle I80, towards one of its ends, on the left of the figure, an arm I82is mounted for pivoting movement about the shaft I8I, the other end I83of said arm being pivoted on the arm I41 of a device G. Towards theother end of the axle I80 an arm I82 is pivoted at IBI the opposite endI83 of which is pivoted on the arm I41 7 of the device G The devices Gand G are fixed to the chassis I81. Each of them comprises, asdescribed, a shock-absorbing box H and compensating devices I and J. Thetube I68 opens into the orifice I69 and the tube I10 opens into theorifice I61 The operation of this system is similar to that of thesystems described above. If, for example, the part of the suspensionwhich involves the left wheel I88 is depressed, the arm I41 rotates in aclockwise direction; the pistons I3I and I32 move towards the left; theliquid which is driven by the piston I3I passes through the shockabsorbing box H without encountering any appreciable resistance, andpushes the group of pistons I32 and I3I towards the right. The liquidwhich is driven from the chamber I36 passes through the shock-absorbingbox H without encountering any appreciable resistance, flows through thetube I10 and fills the space which has been left free by thedisplacement of the pistons I3I-I32. The movement of the pistons I32 andI3I has caused a depression of the part of the suspension which involvesthe wheel I88 equal to that undergone by the part of the suspensionwhich involves the wheel I88. When the suspension is relaxed, the liquidcirculates in the opposite direction; its circulation is in this casebraked by its passing through the shock-absorbing boxes H and H Theadjustment of said shock-absorbing boxes is effected in the manner whichhas been described above.

I claim:

1. Hydraulic damping device especially for vehicles in whichtwo-chambered dampers have the first chamber in each connected to thesec- 0nd chamber in the other and which have a hydraulic circuit and abraking member for braking the liquid in one direction of movement ofthe latter insaid circuit, said braking member being capableofadjustment for the purpose of introducing a greater resistance to thecirculation of theliquid in said one direction and simultaneously alsolimited increase of the resistance of the circulation of the liquid inthe other direction which is much lower than the first mentionedresistance and vice versa, the hydraulic circuit preferably having alsoa gravity tank in communication with said circuit, and means forinterrupting said communication between said circuit and said gravitytank during any periods of time in which an excess pressure obtains insaid circuit.

2. Hydraulic damping device according to claim 1, in which a calibratedorifice is provided in the braking member and a needle controls saidorifice, a mobile member associated with the braking member in whichsaid orifice is formed and a portion integral with said needle, therebeing resilient meansbearing against said portion upon the needleserving resiliently to.

orifice, a mobile member associated with the braking member in whichsaid orifice is formed and a portion integral with said needle, therebeing resilient means bearing against said portion upon the needleserving resiliently to return the mobile member, and wherein means areprovided including an inclined plane portion serving to control theposition of the needle by rotation thereof and thereby longitudinallydisplacing the same for the purpose of braking the liquid in thehydraulic circuit.

5. Hydraulic damping device according to claim 1, in which a pressureresponsive valve is freely mounted and applied to its seat by the effectof excess pressure in the hydraulic circuit, said valve controlling thecommunication between said circuit and the gravity reservoir.

6. Hydraulic damping device according to claim 1, in which a calibratedorifice is provided in the braking member and a pressure respons1vevalve is freely mounted and applied to its seat by the effect of excesspressure in the hydraulic circuit, said valve controlling thecommunication between said circuit and the gravity reservoir, a needlecontrols said orifice, a mobile member associated with the brakingmember in which said orifice is formed and a portion integral with saidneedle, there being resilient means bearing against said portion uponthe needle serving resiliently to return the mobile member.

PAUL HENRI MISTRAL.

